Bar screening apparatus for flowing streams of water and the like



July 20, 1954 s TOLMAN 2,684,157

BAR SCREENING APPARATUS FOR FLOWING STREAMS OF WATER AND THE LIKE FiledFeb. 15, 1949 q 3 Sheets-Sheet l All JNVENTO/Q; 5AMUEL LTQLMAN,

/AL M621.

HTT'Y July 20, 1954 s. L. TOLMAN BAR SCREENING APPARATUS FOR FLOWINGSTREAMS OF WATER AND THE LIKE 3 Sheets-Sheet 2 Filed Feb. 15, 1949 VE/VTOE SAMUEL L.TOL MANJ BY ATT'Y.

July 20, 1954 s TOLMAN BAR SCREENING APPARATUS FOR FLOWING STREAMS OFWATER AND THE LIKE Filed Feb. 15, 1949 3 Sheets-Sheet 3 Elly. 6' 1 1?. 5

Patented July 20, 1954 UNITED STATES TENT OFFICE BAR SCREENING APPARATUSFOR FLOWING STREAMS OF WATER AND THE LIKE ration of Ohio ApplicationFebruary 15, 1949, Serial No. 76,518

8 Claims.

This invention relates to a bar screening apparatus adapted to removetrash, branches, and other large particles, from a flowing stream ofwater, such as a sewage system or a water supply system, or for anyother streams.

An object of the invention is to provide improved apparatus of the abovementioned type, particularly in which the draft means for the screen islocated downstream of the screen bars, with rake teeth extending betweenadjacent bars and traveling from the bottom upward, there preferablybeing a dead plate or scraper plate over which the rakes travel adjacentthe upper portion of their path and after the rakes leave the screenbars and have passed out of the liquid.

As a further development of the above object of the invention, thescreen preferably also includes an adjustable head shaft by which thetension of the endless draft chains is adjusted, the plate beingconnected to move upwardly and downwardly with said head shaft.

Other objects of the invention will appear hereinafter, the novelfeatures and combinations being set forth in the appended claims.

In the accompanying drawings,

Fig. 1 is a side elevational View, with parts in section, showing oneform of screening apparatus incorporating my invention, it beingillustrated as contained in a fiume or sluiceway through which a streamof refuse bearing water flows, as suggested by the arrow;

Fig. 2 is a sectional view taken on the line 2-2 of Fig. 1, looking inthe direction of the arrows;

Fig. 3 is an enlarged view of the head portion of the screeningapparatus of Fig. l, with parts broken away and shown in section;

Fig. 4 is a sectional view taken on the line i i of Fig. 3 and showingone side of the head portion of the screening apparatus;

Fig. 5 is a side elevational view of a modified form of screeningapparatus and associated mechanism;

Fig. 6 is an upstream elevational view of the screening apparatus ofFig. 5; and- Fig. 7 is an enlarged view of the head section of thescreening apparatus of Figs. 5 and 6.

Referring first particularly to Fig. l of the drawings, the screeningapparatus as a whole has its bottom portion extending between thevertical side walls of a flume, sluiccway, or channel ill, through whichwater flows which carries with it material which is to be removed by thescreen, such as trash, branches, or any other large material which maybe floating down with the ward direction.

stream. The normal water level is illustrated in Fig. 1 of the drawingsand, of course, this water level will vary from time to time.

The screening mechanism includes a main frame l l formed of a pair ofopposite channel members i2, i2 which preferably are attached to and fitclosely adjacent the upright sides of the iiume or channel it so thatthe flowing stream of liquid will all flow through the screeningmechanism.

Along the upstream edges of the channel frame members if and downstreamof the upstream flanges thereof there is a pair of angle members 13rigidly attached to said channel frame members l2, which angle membersl3 cooperate with the upstream flanges of the channel frame members l2to provide guideways for a pair of laterally spaced endless draft chainsM.

Near the bottom of the main frame 5! there is a U -shaped guide shoe 5for each of the chains it which reverses the direction of travel of eachchain, or, in other words, provides a friction shoe for the lower end ofeach chain i i as it changes its direction of travel from a downward toan up- The shoes it are preferably rigidly and nonadjustably attached tothe channel frame members 2. The bases of the frame members B2 arepreferably rigidly connected together by a cross channel member is.

At the upper end of the main frame l I there is a head shaft I? providedwith spaced sprockets, one of which is seen at l8 in Fig. 4 of thedrawings, which sprockets l8 mesh with and drive the two chains M. ShaftH is mounted in adjustable journal bearing boxes ill which are mountedfor adjustment relative to the frame I i by screw adjusting mechanisms28 so as to maintain proper tension in the chains i l. Each adjustingmechanism 23 includes clamping devices 2i comprising cooperating slottedangles carried by the boxes l9 and frame channels 12, and clamping nutsand bolts which are, per se, of essentially standard construction.

The shaft ii is driven by a chain and sprocket drive mechanism 22 froman electric motor 23. The motor 23 drives the draft chains i l so thattheir upstream run moves from the bottom of the run upwardly, thedownstream run thereby traveling downwardly.

The channel frame members I2 are not only connected in fixed spacedrelation by the channel iii, but also by one or more additional crosschannels 24, at least one of which is near the head section of the framei l and thus holds said channel members l2 in rigid fixed positionsrelative to each other.

The chain supporting angles it are preferably provided with wear strips25 which actually take the direct bearing contact of the chains it asthey travel along the upstream guides, During the lower portion of thedownstream run, chains i l travel on wear strips 25 which are carried bythe downstream flanges of the channel members i2.

As the chains H3 first start their downward travel they are, however,supported upon wear strips Z'i which are slightly spaced from the wearstrips 26, as clearly illustrated in Fig. 3 of the drawings. A sprocketstripper '28 is also provided for each chain as it comes off thesprocket l8.

Extending transversely between the two chains iii and rigidly attachedthereto is a plurality of spaced toothed rakes 29, the teeth of whichextend between the spaced bars 3 which bars Sil together constitute thescreen 35 which effectively screens out the large material from theflowing stream. Each of the bars 38 of the screen 3! is preferablysupported in cantilever by being attached at a single point to the mainframe H, which is adjacent its bottom. Each said bar 3% is so attachedat its bottom to the cross channel member it of the main frame H bymeans of a cross clamping bar 32 which is bolted to the cross channelit. The clamping bar 32 is preferably notched on its lower edge toreceive the bent up ends of each of the screen bars 36, so as to holdeach of said screen bars in fixed position. Clamping bar 32 may alsohave a right angle extension 33; along its top edge, which is likewisenotched to receive each of the bars 3d.

Adjacent the bottom of the screen 35 there is a hinged toe plate whichis hinged at its upstream edge and at its downstream edge rests on thebottom of the screen 35. The tips of the rake blades preferably justclear the hinged toe plate 3 5 and, in fact, if one of them should touchit, it would merely swing up and then fall down.

It is evident from the above description that the main body of each ofthe rakes 29 is downstream of the screen 3! and that the rake teethextend between the bars 33 and upstream therefrom. Furthermore, it isobvious that substantially the entire raking mechanism, including thedraft chains iii and the supporting frame ii, is downstream relative tothe screen 31, thus providing no obstructions whatever to theaccumulation of the trash, and the like, on the screen 3i. It isfurthermore evident that under normal conditions there will be at leastone and probably more rakes as always interleaved with the screen 3!.

It is evident that the rakes will thereby provide continuous guiding andsupporting means for insuring proper spacing of the bars of the screen83, This is of particular importance in view of the fact that the upperends of the bars are entirely free. which is desired because the bars 3!terminate appreciably below the head shaft ll.

Spaced downstream from the bars 3i] of the screen 35 and in partialoverlapping relation therewith and starting at a position above thewater level there is a dead or scraper plate 35 over which the bottom ofeach rake '29 scrapes as it passes out of the stream and possibly out ofthe trough or channel iii, while traveling along the upstream surface ofscraper plate 35. While traveling through the area of overlap of screen3i and plate 35, rakes 29 travel between said screen and platedownstream of the former and upstream of the latter. Since the scraperplate 35 has its lower edge slightly below the upper end of each bar 39,the bottom of each rake 29 contacts the scraper plate 35 prior to itsleaving the screen bars Obviously, when a rake leaves the upper free endof the screen 3!, the trash carried by the rakes will. in part, fall bygravity down on the scraper plate 35, and the rake in continuing itsupward travel will scrape this material over said plate 35.

The plate 35 is slidably supported along its edges on the angle members13 by supporting plates 36 welded to angles I3 (see Figs. 2 and 4). Saidplate 3 5 is curved into a semi-cylinder at its upper end, thesemi-cylinder being concentric with and spaced from the shaft ll. Saidplate 35 therefore terminates at a position below the axis of the shafti1 and on the downstream side thereof, as clearly illustrated in 3 ofthe drawings.

The scraper plate 35 is connected to the head shaft i i so as to partakeof the up and down adjustment thereof without interfering with its freerotation. To this end the curved upper portion of the plate 35 isprovided at each side with a bearing block 3? which is rigidly attachedto said curved portion of the plate 35 and has hearing contact with theshaft H. An encircling strap 38 attaches each block 3! to the shaft l'iwithout interfering with the free rotation of the shaft ll relativethereto.

It is thus evident that the relative position. of the scraper plate 35and the shaft H is fixed, while the scraper plate 35 is slidable alongthe main frame H so that the relative position of its lower edge and theupper end of the screen 3| may vary from time to time. However, theoverlapping relation of the two along a plane at right angles to thedirection of travel of the chain i4 is maintained at all times so thatin no case will trash, or the like, he removed from the screen 3| by arake 29, except when the bottom of the rake is sliding over the plate35.

When a rake 29 travels over the head shaft ll and thus starts itsdownward run there will be a tendency for the gathering trash to falloff of it under the influence of gravity. Such trash may be received,for example, by a sump 3Q forming a part of the channel H! and providedwith a central drain which can allow water to drain from the trash andrun back into the stream. A pivoted rake scraping or wiping mechanism Mis also preferably provided to cooperate with the rakes 29 to insure athorough cleaning of them. This cleaning takes place while the rakes 29are traveling along the wear strips 2'! provided at the head section ofthe screening mechanism.

The screening mechanism of Figs. 1 to inelusive, has the plane of thescreen 3! inclined to the vertical. In Figs. 6 and '7 of the draw ingsthere is illustrated a modified form of screening apparatus which isquite high and which is shown mounted in a vertical position. This isdesirable particularly in view of the great height of the channel orsluiceway in which it operates.

The screening mechanism of said Figs. 5, 6 and '7 includes a main frameM formed of a pair of spaced-apart frame members 42 which extend betweenthe side walls of a flume, sluiceway or channel and which are held infixed position by a plurality of cross members 43. Endless draft chainsM are carried on opposite sides of the main frame M in a manner evidentfrom the above description of the screen of Figs. 1 to 4. The draftchains 44 travel around foot sprockets 45 and head sprockets 46 carriedon a shaft 41. Head shaft 47 is vertically adjustable to adjust thetension on the chains 44 and is driven from a motor 48 throughappropriate drive mechanism 49.

The draft chains 44 carry cross toothed rakes 50, the teeth of whichextend between adjacent cantilever bars 5| of a flat or plane screen 52.The bottoms of the bars 5| are clamped to the main frame 4| by a crossclamping bar 53 which may correspond with the above described bar 32. Adead or scraper plate 54 is provided, the bottom edge of which overlapsthe upper edge of the screen 52, and the upper end of which terminatesbelow the head shaft 41;

The scraper plate 54 is rigidly attached to the main frame 4! and doesnot partake of the up and down movement of the head shaft 41. Scraper orwiper mechanism 55 is provided to scrape or wipe trash from the rakes 50prior to their passing over the upper end of the scraper plate 54, saidwiper mechanism 55 being carried by said main frame 4|.

The trash scraped from the rakes 50 is delivered to a pan 55 by which itmay be scraped to a shredder of grinder 5'! and reduced to asufiiciently fine state so that it will pass through the screen 52. Theoutput of the shredder or grinder 51 is preferably delivered to thescreen by a chute 58 at a position upstream of the screen 52.

In this screening mechanism it is not necessary to move the scraperplate 54 with the head shaft 41 because the trash is removed from therakes 5t; prior to their passing over said head shaft ll. t is to benoted, however, that the important overlapping relation between thescraper plate 54 and the screen 52 exists and that these parts arespaced apart so that the rakes 5t and the draft chains can passdownstream of the screen 52 and upstream of the scraper plate 54, theysuccessively providing support for the screened material in cooperationwith the rakes until said screened material is ready to be wipedtherefrom by the scraper or wiping mechanism It is thus to be seen thatin both embodiments of the invention in its broad aspects, substantiallythe entire screening mechanism, including particularly the main frameand the draft means for the rakes, is located downstream of the screenso that there will be substantially no interference with theaccumulation of material thereon.

Furthermore, the individual screen bars of the screens are rigidlysupported only at their bottoms, they being guided and maintained in apredetermined lateral position relative to each other by the teeth ofthe cooperating rakes. Furthermore, as the rakes pass upwardly beyondthe extremity of the screen, they are under the influence of theoverlapping scraper plate 54 which cooperates with the rakes to carrythe accumulated refuse until it is ready to be dis charged.

Obviously those skilled in the art may make various changes in thedetails and arrangement of parts without departing from the spirit andscope of the invention as defined by the claims hereto appended, andapplicant therefore wishes not to be restricted to the preciseconstruction herein disclosed.

Having thus described and shown an embodi- 6 ment of the invention, whatit is desired to secure by Letters Patent of the United States is:

1. In a bar screen apparatus for screening material from a stream ofwater including a frame adapted to extend upwardly through a waterstream and above the high water line thereof, spaced toothed rakes,endless draft means connected to said rakes and operative over saidframe, means driving said draft means to cause said rakes to travelupwardly on the upstream side of said frame, a screen on the lowerportion of the upstream side of said frame through which the teeth ofsaid rakes extend, said screen including individual laterally spacedupstanding bars, each attached to said frame at the bottom thereof, anda plate carried by said frame along the upper portion thereof positioneddownstream of and overlapping the upper end of said screen so the rakesride thereover before leaving the upper end of said screen andthereafter in their upward travel.

2. A bar screen apparatus for screening material from a stream of waterincluding a frame adapted to extend upwardly through a water stream andabove the high water line thereof, spaced toothed rakes, endless draftmeans connected to said rakes and operative over said frame, meansdriving said draft means to cause said rakes to travel upwardly on theupstream side of said frame, a screen on the lower portion of theupstream side of said frame through which the teeth of said rakesextend, said screen including individual laterally spaced upstandingbars, each attached to said frame at the bottom thereof while beingotherwise entirely free of said frame, a plate carried by said framealong the upper portion thereof positioned downstream of and overlappingthe upper end of said screen so the rakes ride thereover before leavingsaid screen and thereafter in their upward travel, and means fordischarging material from said apparatus.

3. A bar screen apparatus for removing material from a flowing stream,said screen apparatus including upwardly extending bars in a planesupported at their bottoms, a plate parallel with the plane of said barsand spaced downstream therefrom and overlapping them while extendingupwardly beyond said bars, endless draft means downstream of said bars,toothed rakes carried by said draft means operable when travelingupwardly to have their teeth extend through the spaces between the barsof said screen during the first part of their upward travel and then toslide over said parallel plate during a later portion of their travel,means for discharging material from said apparatus, drive means for saiddraft means including a head shaft, means mounting said head shaft forup and down adjustment to adjust the tension of said draft means, andmeans interconnecting said head shaft and said parallel plate wherebywhen the shaft is adjusted as aforesaid the plate moves with it, saiddrive means being operable to move said rakes from the bottom upwarly ontheir upstream travel.

4. A bar screen apparatus for removing material from a flowing stream,said screen apparatus including laterally spaced upstanding cantilevermounted bars, a plate overlapping a portion of sai bars and spaceddownstream therefrom while extending beyond the ends of said bars,toothed rake means, means operable to move said rake means across saidbars downstream thereof with the teeth thereof extending upstreambetween said bars and then over said plate upstream thereof afterleaving said bars,

said. teeth acting to hold said sereenbars in predetermined spacedrelation, and means for discharging material irom said apparatus.

- 5. A bar screen apparatus for removing material from a flowing stream,said sereen apparatus, including laterally spaced upstanding bars, aplate overlapping a portion of said bars and spaced downstream therefromwhile extending beyond: the ends of said bars, rake means having teethadapted to extend upstream between said laterally spaced bars, meansoperable to move said rake means across said screen downstream thereofwith said rake teeth projecting between said bars as aforesaid and thenover said plate upstream thereof after leaving said screen, and meansfor discharging material from said apparatus.

. 6. A. bar screen apparatus for removing materialfrom a flowing stream,said screen apparatus including upwardly extending bars in a planesupported at their bottoms, a plate parallel with the .plane of saidbars and spaced downstream therefrom and overlapping them whileextending upwardly beyond said bars, said plate including a curvedportion, endless draft means downstream of said bars, toothed rakescarried by said draft means operable when traveling upwardly to havetheir teeth extend through the spaces between the bars of said screenduring the first part of their upward travel and then to slide over saidparallel plate during a later portion of their travel, drive means forsaid draft means including a head shaft, means mounting said head shaftfor up and down adjustment to adjust the tension of said draft means,and means inter connecting said head shaft and the curved portion ofsaid parallel platewhereby when the shaft is adjusted as aforesaid theplate moves with it,.said drive means being operable to move said rakesfrom the bottom upwardly on their upstream travel and over said curvedportion of said plate to discharge material over the latter.

, 7. A, bar-screenapparatus' for removing material from a flowingstream, said screen apparatus including laterally spaced upstandingbars, a'plate spaced downstream therefrom and over- 1 lapping saidvbars, said plate including a curved portion, endlessdraft meansdownstream of said bars, toothed rakes carried by said draft meansoperable when travelling upwardly to have their teeth extend upstream inthe spaces between said bars during the first-part of their upwardtravel and then to travelover said plate during a later portion of theirtravel, and drive means for said draft means including a shaft, saidcurved portionof-said plate extending over said shaft and saiddrive-means being operable to movesaid'rakes upwardly across said barsand plate and over said curved portion of said plate to dischargematerial over the latter.

8. A bar screen apparatus for removing material from a flowing stream,said screen apparatus includinglaterally spaced upstanding bars, meansspaced downstream thereof forming a curved surface and overlapping saidbars, endlessdraft means downstream of said bars, toothed rakes carriedby said draft means operable when traveling upwardly tohave their teethextend upstream in the spaces between said bars during the first part oftheir upward travel and then to travel over said plate during a laterportion of, their travel, and drive means for said draft means operableto move said rakes upwardly across ,said bars andover said surfaceforming means to discharge material over the latter.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,180,798 Spoon Apr. 25, 1916 1,748,151 Stehling Feb. 25, 19302,128,348 Briggs Aug. 30, 1938 2,379,615 Walker July 3, 1945

